 - Who’s Cheating California’s Tough New Vaccine System?Paul A. Offit | September 2, 2017In June 2015, the state enacted Senate Bill 277, mandating that at the beginning of the next academic year, all students had to be vaccinated, including those in private, charter, and parochial schools. It was one of the most restrictive immunization bills in history, and a response to a measles epidemic that started in Southern California at the end of 2014 and eventually spread into 25 states and two Canadian provinces, infecting hundreds of people, mostly children.